302 research outputs found
Genetic diversity and population structure of the threatened temperate woody bamboo Kuruna debilis (Poaceae: Bambusoideae: Arundinarieae) from Sri Lanka based on microsatellite analysis
Species of the temperate woody bamboo genus Kuruna Attigala, Kathriar. & L.G. Clark (Poaceae: Bambusoideae) distributed in Sri Lanka and southern India, are threatened due to deforestation and habitat fragmentation. The current study focused on the tetraploid woody bamboo Kuruna debilis (Thwaites) Attigala, Kathriar. & L.G. Clark, using twelve variable microsatellite loci to assess the genetic diversity and population structure in six known Sri Lankan populations. Due to the rarity of the species, an exhaustive sampling of accessible plants resulted in a total of only 28 individuals. Nonetheless, the allelic diversity was high at most loci and given the limited distances separating populations (\u3c 65 km apart), they exhibited a fairly high genetic differentiation (FST = 0.113) and strong isolation by distance. Structure, neighbour-joining, and neighbour-net analyses concur in grouping the six K. debilis populations into three genetic clusters consistent with the spatial proximity of the populations: one cluster comprised populations from the Piduruthalagala Mountain and Horton Plains, the second cluster consisted of the population from Adams Peak and the last comprised the populations from the Handapan Ella Plains. Due to multiple indicators of high allelic diversity, the population from the northern Horton Plains (LA124) should be targeted for conservation. Moreover, the population found in Adams Peak (LA159) is also genetically important and critical to the conservation of these species due to its unique genetic diversity. As the first population genetics study of Bambusoideae in Sri Lanka, we anticipate that our results will provide a foundation for future comparative population genetics and conservation studies in the country
Analysis of charmonium production at fixed-target experiments in the NRQCD approach
We present an analysis of the existing data on charmonium hadro-production
based on non-relativistic QCD (NRQCD) calculations at the next-to-leading order
(NLO). All the data on J/psi and psi' production in fixed-target experiments
and on pp collisions at low energy are included. We find that the amount of
color octet contribution needed to describe the data is about 1/10 of that
found at the Tevatron
The high energy cosmic ray spectrum from relic particle decay
It has been speculated that the recently detected ultra-high energy cosmic
rays may originate from the decays of relic particles with mass of order
GeV clustered in the halo of our Galaxy. This hypothesis can be
tested through forthcoming measurements of the spectra of both high energy
cosmic nucleons and neutrinos, which are determined in this model by the
physics of QCD fragmentation, with no astrophysical uncertainties. We evolve
fragmentation spectra measured at LEP energies up to the scale of the decaying
particle mass by numerical solution of the DGLAP equations. This enables
incorporation of the effects of supersymmetry on the development of the cascade
and we also allow for decays into many-particle states. The calculated spectral
shape agrees well with present cosmic ray data beyond the
Greisen-Zatsepin-Kuzmin energy.Comment: 30 pages (revtex), 12 figures (eps); Small revisions; Accepted for
publicatio
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Calcium Chloride in Neonatal Parenteral Nutrition Solutions with and without Added Cysteine: Compatibility Studies Using Laser and Micro-Flow Imaging Methodology
Background:
Previous studies of compatibility of calcium chloride (CaCl₂) and phosphates have not included particle counts in the range specified by the United States Pharmacopeia. Micro-flow imaging techniques have been shown to be comparable to light obscuration when determining particle count and size in pharmaceutical solutions.
Objective:
The purpose of this study was to do compatibility testing for parenteral nutrition (PN) solutions containing CaCl₂ using dynamic light scattering and micro-flow imaging techniques.
Methods:
Solutions containing TrophAmine (Braun Medical Inc, Irvine, CA), CaCl₂, and sodium phosphate (NaPhos) were compounded with and without cysteine. All solutions contained standard additives to neonatal PN solutions including dextrose, trace metals, and electrolytes. Control solutions contained no calcium or phosphate. Solutions were analyzed for particle size and particle count. Means of Z-average particle size and particle counts of controls were determined. Study solutions were compared to controls and United States Pharmacopeia (USP) Chapter 788 guidelines. The maximum amount of Phos that was compatible in solutions that contained at least 10 mmol/L of Ca in 2.5% amino acids (AA) was determined. Compatibility of these solutions was verified by performing analyses of 5 repeats of these solutions. Microscopic analyses of the repeats were also performed.
Results:
Amounts of CaCl₂ and NaPhos that were compatible in solutions containing 1.5%, 2%, 2.5%, and 3% AA were determined. The maximum amount of NaPhos that could be added to TrophAmine solutions of > = 2.5% AA containing at least 10 mmol/L of CaCl₂ was 7.5 mmol/L. Adding 50 mg/dL of cysteine increased the amount of NaPhos that could be added to solutions containing 10 mmol/L of CaCl₂ to 10 mmol/L.
Conclusion:
Calcium chloride can be added to neonatal PN solutions containing NaPhos in concentrations that can potentially provide an intravenous intake of adequate amounts of calcium and phosphorus
How Much Pharyngeal Exposure Is “Normal”? Normative Data for Laryngopharyngeal Reflux Events Using Hypopharyngeal Multichannel Intraluminal Impedance (HMII)
Laryngopharyngeal reflux (LPR) can cause atypical symptoms, asthma, and pulmonary fibrosis. The aim of this study was to establish the normative data for LPR using hypopharyngeal multichannel intraluminal impedancepH (HMII)
A re-randomisation design for clinical trials
Background: Recruitment to clinical trials is often problematic, with many trials failing to recruit to their target sample size. As a result, patient care may be based on suboptimal evidence from underpowered trials or non-randomised studies. Methods: For many conditions patients will require treatment on several occasions, for example, to treat symptoms of an underlying chronic condition (such as migraines, where treatment is required each time a new episode occurs), or until they achieve treatment success (such as fertility, where patients undergo treatment on multiple occasions until they become pregnant). We describe a re-randomisation design for these scenarios, which allows each patient to be independently randomised on multiple occasions. We discuss the circumstances in which this design can be used. Results: The re-randomisation design will give asymptotically unbiased estimates of treatment effect and correct type I error rates under the following conditions: (a) patients are only re-randomised after the follow-up period from their previous randomisation is complete; (b) randomisations for the same patient are performed independently; and (c) the treatment effect is constant across all randomisations. Provided the analysis accounts for correlation between observations from the same patient, this design will typically have higher power than a parallel group trial with an equivalent number of observations. Conclusions: If used appropriately, the re-randomisation design can increase the recruitment rate for clinical trials while still providing an unbiased estimate of treatment effect and correct type I error rates. In many situations, it can increase the power compared to a parallel group design with an equivalent number of observations
How To Find Charm in Nuclear Collisions at RHIC and LHC
Measurements of dilepton production from charm decay and Drell-Yan processes
respectively probe the gluon and sea quark distributions in hadronic
collisions. In nucleus-nucleus collisions, these hard scattering processes
constitute a `background' to thermal contributions from the hot matter produced
by the collision. To determine the magnitude and behavior of this background,
we calculate the hard scattering contribution to dilepton production in nuclear
collisions at RHIC and LHC at next to leading order in perturbative QCD.
Invariant mass, rapidity and transverse momentum distributions are presented.
We compare these results to optimistic hydrodynamic estimates of the thermal
dilepton production. We find that charm production from hard scattering is by
far the dominant contribution. Experiments therefore can measure the gluon
distribution in the nuclear target and projectile and, consequently, can
provide new information on gluon shadowing. We then illustrate how experimental
cuts on the rapidity gap between the leptons can aid in reducing the charm
background, thereby enhancing thermal information.Comment: 32 pages, latex, 19 figure
Quantitative Tests of Color Evaporation: Charmonium Production
The color evaporation model simply states that charmonium production is
described by the same dynamics as production, {\em i.e.}, by the
formation of a colored pair. Its color happens to be bleached by
soft final-state interactions. We show that the model gives a complete picture
of charmonium production including low-energy production by proton, photon and
antiproton beams, and high-energy production at the Tevatron and HERA. Our
analysis includes the first next-to-leading-order calculation in the color
evaporation model.Comment: 12 pages (with embedded figures), Latex2.09, uses epsf.sty and
epsfig.sty. Z-compressed postscript version also available at
http://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-942.ps.Z or at
ftp://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-942.ps.
Search for the Supersymmetric Partner of the Top-Quark in Collisions at
We report on a search for the supersymmetric partner of the top quark (stop)
produced in events using of
collisions at recorded with the Collider Detector at
Fermilab. In the case of a light stop squark, the decay of the top quark into
stop plus the lightest supersymmetric particle (LSP) could have a significant
branching ratio. The observed events are consistent with Standard Model production and decay. Hence, we set limits on the branching ratio of
the top quark decaying into stop plus LSP, excluding branching ratios above 45%
for a LSP mass up to 40 {\rm GeV/c}.Comment: 11 pages, 4 figure
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